<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="../../assets/css/base.css">
  <style>
    body {
      display: flex;
    }

    div {
      height: 100px;
      color: white;
      font-size: 20px;
      line-height: 100px;
      text-align: center;
    }

    div:nth-child(1) {
      width: 100px;
      background-color: red;
    }

    div:nth-child(2) {
      flex: 1;
      background-color: orange;
    }

    div:nth-child(3) {
      flex: 2;
      background-color: green;
    }

    div:nth-child(4) {
      flex: 3;
      background-color: blue;
    }
  </style>
</head>

<body>
  <div>100px</div>
  <div>flex: 1;</div>
  <div>flex: 2;</div>
  <div>flex: 3;</div>
</body>

</html>